<!DOCTYPE html>

<html
  xmlns="http://www.w3.org/1999/xhtml"
  >
  <head>
    <title>Line chart &#8211; from Data to Viz</title>

    <meta charset="utf-8" />
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <meta name="generator" content="pandoc" />
    <meta
      name="viewport"
      content="width=device-width, initial-scale=1, shrink-to-fit=no"
    />
    <meta
      name="description"
      content="An extensive description of Line
chart. Definition, examples, input data, common caveats, tool to build it and potential alternatives."
    />
    <meta
      name="keywords"
      content="Data,Dataviz,Datavisualization,Plot,Chart,Graph,R,Python,D3,Learning,Caveat,Pitfall,Mistake,Classification"
    />
    <meta name="author" content="Yan Holtz and Conor Healy" />
    <link rel="icon" href="img/logo/data-to-viz.ico" />

    <!-- Control appearance when share by social media -->
    <meta property="og:title" content="Line chart" />
    <meta
      property="og:image"
      content="https://github.com/holtzy/data_to_viz/raw/master/img/section/LineSmall.png"
    />
    <meta
      property="og:description"
      content="An extensive description of Line
chart. Definition, examples, input data, common caveats, tool to build it and potential alternatives."
    />
    <meta
      property="og:url"
      content="www.data-to-viz.com/caveat/line.html"
    />
    <meta property="og:type" content="website" />

    <style>
      .myheader {
        background-image: url("https://github.com/holtzy/data_to_viz/raw/master/img/overview_RGG_faded.png");
        min-height: 300px;
        background-size: 100% 100%;

        /* Create the parallax scrolling effect */
        background-attachment: fixed;
        background-position: center;
        background-repeat: no-repeat;
        background-size: cover;

        height: 100%;
        width: 100% !important;
      }
      .mytitle {
        text-transform: uppercase;
        font-family: "Montserrat";
        font-size: 200%;
        font-weight: 500;
        letter-spacing: 4px;
      }
    </style>

    <div class="myheader" style="text-align: center">
      <br />
      <a href="http://www.data-to-viz.com"
        ><img
          align="left"
          src="https://github.com/holtzy/data_to_viz/raw/master/img/logo/typo.png"
          style="width: 150px; vertical-align: top; margin-left: 5%"
      /></a>
      <br /><br />
      <br /><br />
      <a href="http://www.data-to-viz.com">
        <img
          src="https://github.com/holtzy/data_to_viz/raw/master/img/section/LineSmall.png"
      /></a>
      <br /><br />
      <p class="mytitle">Line chart</p>
      <p style="color: #d0d0d0">
        <a href="#definition">definition</a> - <a href="#mistake">mistake</a> -
        <a href="#related">related</a> -
        <a href="#code">code</a>
      </p>
    </div>

         <script src="libs/header-attrs-2.27/header-attrs.js"></script>
<script src="libs/jquery-3.6.0/jquery-3.6.0.min.js"></script>
<meta name="viewport" content="width=device-width, initial-scale=1" />
<link href="libs/bootstrap-3.3.5/css/lumen.min.css" rel="stylesheet" />
<script src="libs/bootstrap-3.3.5/js/bootstrap.min.js"></script>
<script src="libs/bootstrap-3.3.5/shim/html5shiv.min.js"></script>
<script src="libs/bootstrap-3.3.5/shim/respond.min.js"></script>
<style>h1 {font-size: 34px;}
       h1.title {font-size: 38px;}
       h2 {font-size: 30px;}
       h3 {font-size: 24px;}
       h4 {font-size: 18px;}
       h5 {font-size: 16px;}
       h6 {font-size: 12px;}
       code {color: inherit; background-color: rgba(0, 0, 0, 0.04);}
       pre:not([class]) { background-color: white }</style>
<script src="libs/navigation-1.1/tabsets.js"></script>
<script src="libs/navigation-1.1/codefolding.js"></script>
<link href="libs/pagedtable-1.1/css/pagedtable.css" rel="stylesheet" />
<script src="libs/pagedtable-1.1/js/pagedtable.js"></script>       <style type="text/css">
      code {
        white-space: pre;
      }
    </style>
    <style type="text/css">
      pre > code.sourceCode { white-space: pre; position: relative; }
      pre > code.sourceCode > span { line-height: 1.25; }
      pre > code.sourceCode > span:empty { height: 1.2em; }
      .sourceCode { overflow: visible; }
      code.sourceCode > span { color: inherit; text-decoration: inherit; }
      div.sourceCode { margin: 1em 0; }
      pre.sourceCode { margin: 0; }
      @media screen {
      div.sourceCode { overflow: auto; }
      }
      @media print {
      pre > code.sourceCode { white-space: pre-wrap; }
      pre > code.sourceCode > span { display: inline-block; text-indent: -5em; padding-left: 5em; }
      }
      pre.numberSource code
        { counter-reset: source-line 0; }
      pre.numberSource code > span
        { position: relative; left: -4em; counter-increment: source-line; }
      pre.numberSource code > span > a:first-child::before
        { content: counter(source-line);
          position: relative; left: -1em; text-align: right; vertical-align: baseline;
          border: none; display: inline-block;
          -webkit-touch-callout: none; -webkit-user-select: none;
          -khtml-user-select: none; -moz-user-select: none;
          -ms-user-select: none; user-select: none;
          padding: 0 4px; width: 4em;
          color: #aaaaaa;
        }
      pre.numberSource { margin-left: 3em; border-left: 1px solid #aaaaaa;  padding-left: 4px; }
      div.sourceCode
        {   }
      @media screen {
      pre > code.sourceCode > span > a:first-child::before { text-decoration: underline; }
      }
      code span.al { color: #ff0000; font-weight: bold; } /* Alert */
      code span.an { color: #60a0b0; font-weight: bold; font-style: italic; } /* Annotation */
      code span.at { color: #7d9029; } /* Attribute */
      code span.bn { color: #40a070; } /* BaseN */
      code span.bu { color: #008000; } /* BuiltIn */
      code span.cf { color: #007020; font-weight: bold; } /* ControlFlow */
      code span.ch { color: #4070a0; } /* Char */
      code span.cn { color: #880000; } /* Constant */
      code span.co { color: #60a0b0; font-style: italic; } /* Comment */
      code span.cv { color: #60a0b0; font-weight: bold; font-style: italic; } /* CommentVar */
      code span.do { color: #ba2121; font-style: italic; } /* Documentation */
      code span.dt { color: #902000; } /* DataType */
      code span.dv { color: #40a070; } /* DecVal */
      code span.er { color: #ff0000; font-weight: bold; } /* Error */
      code span.ex { } /* Extension */
      code span.fl { color: #40a070; } /* Float */
      code span.fu { color: #06287e; } /* Function */
      code span.im { color: #008000; font-weight: bold; } /* Import */
      code span.in { color: #60a0b0; font-weight: bold; font-style: italic; } /* Information */
      code span.kw { color: #007020; font-weight: bold; } /* Keyword */
      code span.op { color: #666666; } /* Operator */
      code span.ot { color: #007020; } /* Other */
      code span.pp { color: #bc7a00; } /* Preprocessor */
      code span.sc { color: #4070a0; } /* SpecialChar */
      code span.ss { color: #bb6688; } /* SpecialString */
      code span.st { color: #4070a0; } /* String */
      code span.va { color: #19177c; } /* Variable */
      code span.vs { color: #4070a0; } /* VerbatimString */
      code span.wa { color: #60a0b0; font-weight: bold; font-style: italic; } /* Warning */
            div.sourceCode {
        overflow-x: visible;
      }
          </style>
        <style type="text/css">
      pre:not([class]) {
        background-color: white;
      }
    </style>
           <style type="text/css">
      h1 {
        font-size: 34px;
      }
      h1.title {
        font-size: 38px;
      }
      h2 {
        font-size: 30px;
      }
      h3 {
        font-size: 24px;
      }
      h4 {
        font-size: 18px;
      }
      h5 {
        font-size: 16px;
      }
      h6 {
        font-size: 12px;
      }
      .table th:not([align]) {
        text-align: left;
      }
          </style>
         <link
      rel="stylesheet"
      href="style.css"
      type="text/css"
      
    />
      </head>

  <body>
        <style type="text/css">
      .main-container {
        max-width: 940px;
        margin-left: auto;
        margin-right: auto;
      }
      code {
        color: inherit;
        background-color: rgba(0, 0, 0, 0.04);
      }
      img {
        max-width: 100%;
        height: auto;
      }
      .tabbed-pane {
        padding-top: 12px;
      }
      button.code-folding-btn:focus {
        outline: none;
      }
    </style>

     
    <div class="container-fluid main-container">
      <!-- tabsets -->
      <script>
        $(document).ready(function () {
          window.buildTabsets("TOC");
        });
      </script>

      <!-- code folding -->
            <style type="text/css">
        .code-folding-btn {
          margin-bottom: 4px;
        }
      </style>
      <script>
        $(document).ready(function () {
                          window.initializeCodeFolding("hide" === "show");
                });
      </script>
         
                    <div class="fluid-row" id="header">
                        <div class="btn-group pull-right">
              <button
                type="button"
                class="btn btn-default btn-xs dropdown-toggle"
                data-toggle="dropdown"
                aria-haspopup="true"
                aria-expanded="false"
              >
                <span>Show Code</span> <span class="caret"></span>
              </button>
              <ul class="dropdown-menu" style="min-width: 50px">
                                <li><a id="rmd-show-all-code" href="#">Show All Code</a></li>
                <li><a id="rmd-hide-all-code" href="#">Hide All Code</a></li>
                                </ul>
            </div>

                         </div>

              <div class="mycontent">
<div id="definition" class="section level1">
<h1>Definition</h1>
<hr />
<p>A <code>line chart</code> or line graph displays the evolution of one
or several numeric variables. Data points are connected by straight line
segments. It is similar to a <a
href="https://www.data-to-viz.com/graph/scatter.html">scatter plot</a>
except that the measurement points are ordered (typically by their
x-axis value) and joined with straight line segments. A line chart is
often used to visualize a trend in data over intervals of time – a time
series – thus the line is often drawn chronologically.</p>
<p><br></p>
<p>The following example shows the evolution of the <a
href="https://www.data-to-viz.com/story/TwoNumOrdered.html">bitcoin
price</a> between April 2013 and April 2018. Data comes from the <a
href="https://www.data-to-viz.com/story/TwoNumOrdered.html">CoinMarketCap</a>
website.</p>
<div class="sourceCode" id="cb1"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb1-1"><a href="#cb1-1" tabindex="-1"></a><span class="co"># Libraries</span></span>
<span id="cb1-2"><a href="#cb1-2" tabindex="-1"></a><span class="fu">library</span>(tidyverse)</span>
<span id="cb1-3"><a href="#cb1-3" tabindex="-1"></a><span class="fu">library</span>(hrbrthemes)</span>
<span id="cb1-4"><a href="#cb1-4" tabindex="-1"></a><span class="fu">library</span>(plotly)</span>
<span id="cb1-5"><a href="#cb1-5" tabindex="-1"></a><span class="fu">library</span>(patchwork)</span>
<span id="cb1-6"><a href="#cb1-6" tabindex="-1"></a><span class="fu">library</span>(babynames)</span>
<span id="cb1-7"><a href="#cb1-7" tabindex="-1"></a><span class="fu">library</span>(viridis)</span>
<span id="cb1-8"><a href="#cb1-8" tabindex="-1"></a></span>
<span id="cb1-9"><a href="#cb1-9" tabindex="-1"></a><span class="co"># Load dataset from github</span></span>
<span id="cb1-10"><a href="#cb1-10" tabindex="-1"></a>data <span class="ot">&lt;-</span> <span class="fu">read.table</span>(<span class="st">&quot;https://raw.githubusercontent.com/holtzy/data_to_viz/master/Example_dataset/3_TwoNumOrdered.csv&quot;</span>, <span class="at">header=</span>T)</span>
<span id="cb1-11"><a href="#cb1-11" tabindex="-1"></a>data<span class="sc">$</span>date <span class="ot">&lt;-</span> <span class="fu">as.Date</span>(data<span class="sc">$</span>date)</span>
<span id="cb1-12"><a href="#cb1-12" tabindex="-1"></a></span>
<span id="cb1-13"><a href="#cb1-13" tabindex="-1"></a><span class="co"># plot</span></span>
<span id="cb1-14"><a href="#cb1-14" tabindex="-1"></a>data <span class="sc">%&gt;%</span></span>
<span id="cb1-15"><a href="#cb1-15" tabindex="-1"></a>  <span class="fu">ggplot</span>( <span class="fu">aes</span>(<span class="at">x=</span>date, <span class="at">y=</span>value)) <span class="sc">+</span></span>
<span id="cb1-16"><a href="#cb1-16" tabindex="-1"></a>    <span class="fu">geom_line</span>(<span class="at">color=</span><span class="st">&quot;#69b3a2&quot;</span>) <span class="sc">+</span></span>
<span id="cb1-17"><a href="#cb1-17" tabindex="-1"></a>    <span class="fu">ggtitle</span>(<span class="st">&quot;Evolution of Bitcoin price&quot;</span>) <span class="sc">+</span></span>
<span id="cb1-18"><a href="#cb1-18" tabindex="-1"></a>    <span class="fu">ylab</span>(<span class="st">&quot;bitcoin price ($)&quot;</span>) <span class="sc">+</span></span>
<span id="cb1-19"><a href="#cb1-19" tabindex="-1"></a>    <span class="fu">theme_ipsum</span>()</span></code></pre></div>
<p><img src="line_files/figure-html/unnamed-chunk-1-1.png" width="960" style="display: block; margin: auto;" /></p>
<p><em>Note</em>: You can read more about this project <a
href="https://www.data-to-viz.com/story/TwoNumOrdered.html">here</a>.</p>
</div>
<div id="what-for" class="section level1">
<h1>What for</h1>
<hr />
<p>Line chart can be used to show the evolution of one (like above) or
several variables. Here is an example showing the evolution of three
baby name frequencies in the US between 1880 and 2015. Note that this
works well for a low number of group to display. With more than a few,
the graphic get cluttered and becomes unreadable. This is called a <a
href="https://www.data-to-viz.com/caveat/spaghetti.html">spaghetti
chart</a> and you can read more about it <a
href="https://www.data-to-viz.com/caveat/spaghetti.html">here</a>.</p>
<div class="sourceCode" id="cb2"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb2-1"><a href="#cb2-1" tabindex="-1"></a><span class="co"># Load dataset from github</span></span>
<span id="cb2-2"><a href="#cb2-2" tabindex="-1"></a>don <span class="ot">&lt;-</span> babynames <span class="sc">%&gt;%</span></span>
<span id="cb2-3"><a href="#cb2-3" tabindex="-1"></a>  <span class="fu">filter</span>(name <span class="sc">%in%</span> <span class="fu">c</span>(<span class="st">&quot;Ashley&quot;</span>, <span class="st">&quot;Patricia&quot;</span>, <span class="st">&quot;Helen&quot;</span>)) <span class="sc">%&gt;%</span></span>
<span id="cb2-4"><a href="#cb2-4" tabindex="-1"></a>  <span class="fu">filter</span>(sex<span class="sc">==</span><span class="st">&quot;F&quot;</span>)</span>
<span id="cb2-5"><a href="#cb2-5" tabindex="-1"></a></span>
<span id="cb2-6"><a href="#cb2-6" tabindex="-1"></a><span class="co"># Plot</span></span>
<span id="cb2-7"><a href="#cb2-7" tabindex="-1"></a>don <span class="sc">%&gt;%</span></span>
<span id="cb2-8"><a href="#cb2-8" tabindex="-1"></a>  <span class="fu">ggplot</span>( <span class="fu">aes</span>(<span class="at">x=</span>year, <span class="at">y=</span>n, <span class="at">group=</span>name, <span class="at">color=</span>name)) <span class="sc">+</span></span>
<span id="cb2-9"><a href="#cb2-9" tabindex="-1"></a>    <span class="fu">geom_line</span>() <span class="sc">+</span></span>
<span id="cb2-10"><a href="#cb2-10" tabindex="-1"></a>    <span class="fu">scale_color_viridis</span>(<span class="at">discrete =</span> <span class="cn">TRUE</span>) <span class="sc">+</span></span>
<span id="cb2-11"><a href="#cb2-11" tabindex="-1"></a>    <span class="fu">ggtitle</span>(<span class="st">&quot;Popularity of American names in the previous 30 years&quot;</span>) <span class="sc">+</span></span>
<span id="cb2-12"><a href="#cb2-12" tabindex="-1"></a>    <span class="fu">theme_ipsum</span>() <span class="sc">+</span></span>
<span id="cb2-13"><a href="#cb2-13" tabindex="-1"></a>    <span class="fu">ylab</span>(<span class="st">&quot;Number of babies born&quot;</span>)</span></code></pre></div>
<p><img src="line_files/figure-html/unnamed-chunk-2-1.png" width="960" style="display: block; margin: auto;" /></p>
</div>
<div id="variation" class="section level1">
<h1>Variation</h1>
<hr />
<p>If the number of data points is low, it is advised to represent each
individual observation with a dot. It allows to understand when exactly
the observation have been made:</p>
<div class="sourceCode" id="cb3"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb3-1"><a href="#cb3-1" tabindex="-1"></a>data <span class="sc">%&gt;%</span></span>
<span id="cb3-2"><a href="#cb3-2" tabindex="-1"></a>  <span class="fu">tail</span>(<span class="dv">10</span>) <span class="sc">%&gt;%</span></span>
<span id="cb3-3"><a href="#cb3-3" tabindex="-1"></a>  <span class="fu">ggplot</span>( <span class="fu">aes</span>(<span class="at">x=</span>date, <span class="at">y=</span>value)) <span class="sc">+</span></span>
<span id="cb3-4"><a href="#cb3-4" tabindex="-1"></a>    <span class="fu">geom_line</span>(<span class="at">color=</span><span class="st">&quot;#69b3a2&quot;</span>) <span class="sc">+</span></span>
<span id="cb3-5"><a href="#cb3-5" tabindex="-1"></a>    <span class="fu">geom_point</span>(<span class="at">color=</span><span class="st">&quot;#69b3a2&quot;</span>, <span class="at">size=</span><span class="dv">4</span>) <span class="sc">+</span></span>
<span id="cb3-6"><a href="#cb3-6" tabindex="-1"></a>    <span class="fu">ggtitle</span>(<span class="st">&quot;Cuting&quot;</span>) <span class="sc">+</span></span>
<span id="cb3-7"><a href="#cb3-7" tabindex="-1"></a>    <span class="fu">ylab</span>(<span class="st">&quot;bitcoin price ($)&quot;</span>) <span class="sc">+</span></span>
<span id="cb3-8"><a href="#cb3-8" tabindex="-1"></a>    <span class="fu">theme_ipsum</span>()</span></code></pre></div>
<p><img src="line_files/figure-html/unnamed-chunk-3-1.png" width="960" style="display: block; margin: auto;" /></p>
<p>Note that lines are also used to show trends in a scatterplot. Here
is an example using Smoothed conditional means and showing confidence
interval around it:</p>
<div class="sourceCode" id="cb4"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb4-1"><a href="#cb4-1" tabindex="-1"></a><span class="fu">ggplot</span>(mpg, <span class="fu">aes</span>(displ, hwy)) <span class="sc">+</span></span>
<span id="cb4-2"><a href="#cb4-2" tabindex="-1"></a>  <span class="fu">geom_point</span>() <span class="sc">+</span></span>
<span id="cb4-3"><a href="#cb4-3" tabindex="-1"></a>  <span class="fu">geom_smooth</span>(<span class="at">color=</span><span class="st">&quot;#69b3a2&quot;</span>) <span class="sc">+</span></span>
<span id="cb4-4"><a href="#cb4-4" tabindex="-1"></a>  <span class="fu">theme_ipsum</span>()</span></code></pre></div>
<p><img src="line_files/figure-html/unnamed-chunk-4-1.png" width="672" style="display: block; margin: auto;" /></p>
<p><em>Note</em>: this example comes from the <a
href="http://ggplot2.tidyverse.org/reference/geom_smooth.html">ggplot2
documentaion</a>.</p>
</div>
<div id="mistake" class="section level1">
<h1>Common caveats</h1>
<hr />
<p>The line chart is subject to a lot of discussion concerning potential
caveats. Here is an overview:</p>
<ul>
<li><a href="https://www.data-to-viz.com/caveat/cut_y_axis.html">To cut
or not to cut the Y axis</a>? Wether or not the Y axis must start at 0
is a hot topic leading to intense debates. The graphic below presents
the same data, starting at 0 (left) or not (right). Generally, line plot
do not need to start at 0 since it allows to observe patterns more
efficiently, but you probably want to learn more about it <a
href="https://www.data-to-viz.com/caveat/cut_y_axis.html">here</a>.</li>
</ul>
<div class="sourceCode" id="cb5"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb5-1"><a href="#cb5-1" tabindex="-1"></a>p1 <span class="ot">&lt;-</span> data <span class="sc">%&gt;%</span></span>
<span id="cb5-2"><a href="#cb5-2" tabindex="-1"></a>  <span class="fu">tail</span>(<span class="dv">10</span>) <span class="sc">%&gt;%</span></span>
<span id="cb5-3"><a href="#cb5-3" tabindex="-1"></a>  <span class="fu">ggplot</span>( <span class="fu">aes</span>(<span class="at">x=</span>date, <span class="at">y=</span>value)) <span class="sc">+</span></span>
<span id="cb5-4"><a href="#cb5-4" tabindex="-1"></a>    <span class="fu">geom_line</span>(<span class="at">color=</span><span class="st">&quot;#69b3a2&quot;</span>) <span class="sc">+</span></span>
<span id="cb5-5"><a href="#cb5-5" tabindex="-1"></a>    <span class="fu">geom_point</span>(<span class="at">color=</span><span class="st">&quot;#69b3a2&quot;</span>, <span class="at">size=</span><span class="dv">4</span>) <span class="sc">+</span></span>
<span id="cb5-6"><a href="#cb5-6" tabindex="-1"></a>    <span class="fu">ggtitle</span>(<span class="st">&quot;Not cuting&quot;</span>) <span class="sc">+</span></span>
<span id="cb5-7"><a href="#cb5-7" tabindex="-1"></a>    <span class="fu">ylab</span>(<span class="st">&quot;bitcoin price ($)&quot;</span>) <span class="sc">+</span></span>
<span id="cb5-8"><a href="#cb5-8" tabindex="-1"></a>    <span class="fu">theme_ipsum</span>() <span class="sc">+</span></span>
<span id="cb5-9"><a href="#cb5-9" tabindex="-1"></a>    <span class="fu">ylim</span>(<span class="dv">0</span>,<span class="dv">10000</span>)</span>
<span id="cb5-10"><a href="#cb5-10" tabindex="-1"></a></span>
<span id="cb5-11"><a href="#cb5-11" tabindex="-1"></a>p2 <span class="ot">&lt;-</span> data <span class="sc">%&gt;%</span></span>
<span id="cb5-12"><a href="#cb5-12" tabindex="-1"></a>  <span class="fu">tail</span>(<span class="dv">10</span>) <span class="sc">%&gt;%</span></span>
<span id="cb5-13"><a href="#cb5-13" tabindex="-1"></a>  <span class="fu">ggplot</span>( <span class="fu">aes</span>(<span class="at">x=</span>date, <span class="at">y=</span>value)) <span class="sc">+</span></span>
<span id="cb5-14"><a href="#cb5-14" tabindex="-1"></a>    <span class="fu">geom_line</span>(<span class="at">color=</span><span class="st">&quot;#69b3a2&quot;</span>) <span class="sc">+</span></span>
<span id="cb5-15"><a href="#cb5-15" tabindex="-1"></a>    <span class="fu">geom_point</span>(<span class="at">color=</span><span class="st">&quot;#69b3a2&quot;</span>, <span class="at">size=</span><span class="dv">4</span>) <span class="sc">+</span></span>
<span id="cb5-16"><a href="#cb5-16" tabindex="-1"></a>    <span class="fu">ggtitle</span>(<span class="st">&quot;Cuting&quot;</span>) <span class="sc">+</span></span>
<span id="cb5-17"><a href="#cb5-17" tabindex="-1"></a>    <span class="fu">ylab</span>(<span class="st">&quot;bitcoin price ($)&quot;</span>) <span class="sc">+</span></span>
<span id="cb5-18"><a href="#cb5-18" tabindex="-1"></a>    <span class="fu">theme_ipsum</span>()</span>
<span id="cb5-19"><a href="#cb5-19" tabindex="-1"></a></span>
<span id="cb5-20"><a href="#cb5-20" tabindex="-1"></a>p1 <span class="sc">+</span> p2</span></code></pre></div>
<p><img src="line_files/figure-html/unnamed-chunk-5-1.png" width="960" style="display: block; margin: auto;" /></p>
<ul>
<li>If you need to compare the evolution of 2 different variables, do
not use <a href="https://www.data-to-viz.com/caveat/dual_axis.html">dual
axis</a>. Indeed dual axis can show very different results depending on
what range you apply to the axis. <a
href="https://www.data-to-viz.com/caveat/dual_axis.html">Read more about
it</a>.</li>
<li>Mind the <a
href="https://www.data-to-viz.com/caveat/spaghetti.html">spaghetti
chart</a>: too many lines make the chart unreadable.</li>
<li>Think about the <a
href="https://www.data-to-viz.com/caveat/aspect_ratio.html">aspect
ratio</a> of the graphic, extreme ratio make the chart unreadable.</li>
</ul>
</div>
<div id="related" class="section level1">
<h1>Related</h1>
<hr />
<div class="row">
<div class="col-lg-3 col-md-6 col-sm-6">
<a href="https://www.data-to-viz.com/graph/line.html" class="btn btn-primary mybtnrelated" style="margin-bottom:4px;white-space: normal !important;">
<img  src="https://github.com/holtzy/data_to_viz/raw/master/img/section/LineSmall.png">
<p class="mytitlerelated">
Line plot
</p>
<p class="mytextrelated">
Displays the evolution of one or several numeric variables.
</p>
</a>
</div>
<div class="col-lg-3 col-md-6 col-sm-6">
<a href="https://www.data-to-viz.com/graph/area.html" class="btn btn-primary mybtnrelated" style="margin-bottom:4px;white-space: normal !important;">
<img  src="https://github.com/holtzy/data_to_viz/raw/master/img/section/AreaSmall.png">
<p class="mytitlerelated">
Area chart
</p>
<p class="mytextrelated">
Basically a line graph, filling the area under the curve.
</p>
</a>
</div>
<div class="col-lg-3 col-md-6 col-sm-6">
<a href="https://www.data-to-viz.com/graph/stackedarea.html" class="btn btn-primary mybtnrelated" style="margin-bottom:4px;white-space: normal !important;">
<img  src="https://github.com/holtzy/data_to_viz/raw/master/img/section/StackedAreaSmall.png">
<p class="mytitlerelated">
Stacked area chart
</p>
<p class="mytextrelated">
Displays the evolution of the value of several groups on the same
graphic
</p>
</a>
</div>
<div class="col-lg-3 col-md-6 col-sm-6">
<a href="https://www.data-to-viz.com/graph/streamgraph.html" class="btn btn-primary mybtnrelated" style="margin-bottom:4px;white-space: normal !important;">
<img  src="https://github.com/holtzy/data_to_viz/raw/master/img/section/StreamSmall.png">
<p class="mytitlerelated">
Streamgraph
</p>
<p class="mytextrelated">
A stacked area graph displaced around a central axis, resulting in a
flowing, organic shape
</p>
</a>
</div>
</div>
</div>
<div id="code" class="section level1">
<h1>Build your own</h1>
<hr />
<p>The <a href="https://r-graph-gallery.com/line-plot.html">R</a>, <a
href="https:/python-graph-gallery.com/line-chart/">Python</a>, <a
href="https://www.react-graph-gallery.com/line-chart">React</a> and <a
href="https://d3-graph-gallery.com/line.html">D3</a> graph galleries are
4 websites providing hundreds of chart example, always providing the
reproducible code. Click the button below to see how to build the chart
you need with your favorite programing language.</p>
<p>
<a href="https://r-graph-gallery.com/line-plot.html" class="btn btn-primary">R
graph gallery</a>
<a href="https://python-graph-gallery.com/line-chart/" class="btn btn-primary">Python
gallery</a>
<a href="https://www.react-graph-gallery.com/line-chart" class="btn btn-primary">React
gallery</a>
<a href="https://d3-graph-gallery.com/line.html" class="btn btn-primary">D3
gallery</a>
</p>
</div>
</div>

          <section
            id="form"
            style="
              margin-top: 70px;
              padding-bottom: 70px;
              padding-top: 70px;
              background-color: #f8f9fa;
            "
          >
            <div class="container">
              <div
                style="
                  display: flex;
                  flex-direction: column;
                  align-items: center;
                "
              >
                <h2 style="font-size: 44px" class="text-center">
                  Dataviz decision tree
                </h2>
                <p
                  class="text-center"
                  style="max-width: 600px; font-size: 18px"
                >
                  <a href="https://www.data-to-viz.com">Data To Viz</a> is a
                  comprehensive <b>classification of chart types</b> organized
                  by data input format. Get a high-resolution version of our
                  decision tree delivered to your inbox now!
                </p>
                <div
                  style="
                    margin-top: -50px;
                    width: 100%;
                    display: flex;
                    justify-content: center;
                  "
                >
                  <script
                    async
                    data-uid="8010f15fd2"
                    src="https://prodigious-trailblazer-3628.ck.page/8010f15fd2/index.js"
                  ></script>
                </div>
                <br />
                <div class="text-center">
                  <img
                    class="img-fluid"
                    src="../img/poster/poster_small.png"
                    alt="High Resolution Poster"
                    style="max-width: 400px"
                  />
                </div>
              </div>
            </div>
          </section>

           &nbsp;
<hr />
<p style="text-align: center;">A work by <a href="https://www.yan-holtz.com/">Yan Holtz</a> for <a href="https://data-to-viz.com">data-to-viz.com</a></p>

<!-- Add icon library -->
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">

<!-- Add font awesome icons -->
<p style="text-align: center;">
	<a href="https://twitter.com/r_graph_gallery?lang=en" class="fa fa-twitter"></a>
	<a href="https://www.linkedin.com/in/yan-holtz-2477534a/" class="fa fa-linkedin"></a>
	<a href="https://github.com/holtzy/" class="fa fa-github"></a>
</p>

<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=UA-79254642-3"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'UA-79254642-3');
</script>
<script>
var getOutboundLink = function(url) {
	gtag('event', 'click', {
		'event_category': 'outbound',
		'event_label': url,
		'transport_type': 'beacon',
		'event_callback': function(){document.location = url;}
	});
}
</script>

&nbsp;                </div>

    <script>

      // add bootstrap table styles to pandoc tables
      function bootstrapStylePandocTables() {
        $('tr.header').parent('thead').parent('table').addClass('table table-condensed');
      }
      $(document).ready(function () {
        bootstrapStylePandocTables();
      });

          </script>
       </body>
</html>
